Thursday, January 13, 2011

Flower Show Handout

Bring Spring into Your Home – By Forcing Daffodils

by David Smith and Elaine Widmer

During the cold winter months, when the world turns white, gray and dark, gardeners yearn for the color of spring flowers and the sweet smell of spring. The good news is each of us can bring spring in our home each winter if we learn the skill of bulb forcing.

David Smith, the propagator and director of horticulture at White Flower Farm from 1954 to 1990, defines forcing bulbs as “getting them to flower at the time you want them to rather than allowing them to flower at their natural time.” His expertise in forcing bulbs, shrubs and perennials allowed him to earn numerous awards for White Flower Farm at the Boston flower shows. The Connecticut Horticultural Society is fortunate to have David assisting us with our flower show exhibit. He not only takes the responsibility for the forcing of our daffodils, primrose and grasses but also shares his 70 years of knowledge with members of CHS.

To learn how to have a ‘breath of spring’ in your home next winter, follow David’s 10 steps to forcing daffodils.

1.BULB SELECTION – David has found the following daffodil varieties to be most reliable: Paperwhites*, Soleil d’Or*, Ice Follies, King Alfred, and the miniature daffodils Tele a tete, Jack Snipe, and Topolino. You’ll find these in your bulb catalogues and local nurseries. Study the description of the various bulb varieties and their flowering times. In general they will bloom early, mid-season or late. (*Both paperwhites and Soleil D’Or are cooled ahead of time by the growers. Therefore, these bulbs will be ready for your windowsill 2-3 weeks after potting and can be used for the holiday season.)

2.BULB PURCHASE – Buy your bulbs in September. Look for a plump bulb that is firm to the touch. Remove any loose scales and tear off old dried out roots from the bottom of the bulb. If the bulb is sprouting you can still use it if all the other characteristics are fine.

3.CONTAINERS – If you’re using a plastic pot, clean and dry it. If you’re using a new clay pot, soak it in water overnight. Clay pots can be dry after firing. Soaking ensures that the pot doesn’t rob moisture from the soil. Make sure the clay pot is DRY before planting your bulbs because a wet pot may retain a dark or dirty look on the exterior of the pot.

4.SOIL– Buy a soilless mix of perlite or vermiculite, peat, and loamy soil. There’s no need to fertilize the bulb as it contains all the food it needs for the first season. If you want to plant the bulbs after forcing, use a 20/20/20 fertilizer to provide the bulb’s required nutrients for the next year. (If you use Paperwhites, fertilizer can be eliminated as they should be discarded after blooming).

5.PLANTING– Plant in early October. The tip (nose) of the bulb should extend ¼” above the top of the pot. David uses a 6” plastic pot and puts 5-6 single bulbs in the pot, depending on the bulb’s variety and size. (TIP: If the bulbs are double or triples, known as double or triple nosed, do not break them apart unless they are loose since the smaller bulb is getting nutrients from the larger one). Once the bulbs are planted, use the very tips of your fingers to gently push the soil down around the bulbs. The soil should not be firmly packed. Water the pot thoroughly but do not allow it to sit in the water. (Clay pots will require more frequent watering as they dry out more quickly than plastic).

6.COOLING PERIOD - Leave your pot of bulbs (water as necessary), outside until Thanksgiving or until night temperatures approach a low of 34 degrees. From the potting time until the time that you place the pot in a sunny window, you will need to provide the bulbs 8 to 12 weeks of cold temperatures. So, when you bring the bulbs in the house, put the pot in a root cellar or a cool room with a maximum temperature of 50 degrees and a minimum temperature of 40 until you’ve accounted for 8 to 12 weeks from the original potting date. The lower the temperature the more gradually your daffodils will grow. If the temperature is more than 60 to 65 degrees your plants will get leggy and may flop when in bloom.

7.MAINTENANCE– While the bulbs are in their ‘cooling off’ period, keep the soil moist. Water the pot until the water runs out but don’t let the pot sit in the water. One tip for determining whether your bulbs need water is to pick up the pot and feel its weight. If it’s very light, give it some water. If heavy, it’s probably OK. If you notice the bulbs pushing the soil up out of the pot while rooting, add water to the pot. The water will filter the loose soil down and around the bulbs. If necessary push the soil down again using the tips of your fingers.

8.BLOOM TIME – When you see growth appearing, the bulbs have developed a solid root system. It is time to move the pot to a sunny window with a temperature of around 65 degrees. Turn the pot regularly so the daffodils get an equal amount of sun on all sides. This ensures the plants grow straight. Continue watering as described above. In about 4 weeks your daffodils will begin to bloom, depending upon a couple variables – the bulb variety and the weather. There can be a difference in bloom time of 4 to 5 weeks between an early and late flowering variety. The weather also impacts the flowering timeframe. In cloudy weather, the daffodils will stay at a lower temperature when placed by the window. If the sun shines, a temperature of 55 degrees can rise to 75 degrees within an hour resulting in a much quicker bloom time.

9.ENJOY THE BLOOMS – Once the daffodils are in bloom, move them to a cooler place in your house. You will have ‘spring’ in your home for a longer period.

10.PLANTING THE FORCED BULBS – Once the daffodils finish blooming and reasonably good weather comes along, put the pot of bulbs on the north side of the house or in the shade. Leave the pot there until the leaves die back (June or July). Plant the bulbs while they are dormant. Pull the bulbs apart before planting and place them 3 to 4 inches apart with the nose 5 to 6 inches below the top of the soil. Sprinkle bulb fertilizer in the hole before planting and on top of the soil to increase the probability of bloom the following year.

To have daffodils in bloom over a long period, David suggests staggering the planting of your bulbs for forcing. Between early October and Thanksgiving plant 4 to 6 pots of daffodils. Bring one pot of daffodils into a sunny window each week, once growth begins to occur. You’ll be rewarded by being able to have spring flowers in your home during the cold winter months.

David Smith has over 70 years experience propagating shrubs, perennials, and forcing bulbs. His career began in England. In 1954 he relocated to the United States after being recruited to join White Flower Farm. Since David’s retirement in 1990 he has continued to assist CHS by sharing his knowledge and expertise with its members.

Elaine Widmer is a member of the Connecticut Horticultural Society’s Education Committee, an avid gardener and photographer in Connecticut.